Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and readOnlyHint=false. The description adds real value beyond that: it explains the SyncToken concurrency requirement and the return of the saved record with a new SyncToken. It doesn't detail what gets destroyed or the permission scope, so a 4 rather than 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences: the first front-loads the operation and prerequisites, the second covers the return value. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers purpose, prerequisites, and return value, and works with a rich nested-schema entity param and opposing annotations. It doesn't mention the sparse:false destructive full-update behavior in the description text, but that detail lives in the schema; a 4 given how much the schema and annotations already carry.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so baseline is 3. The description reinforces the Id/SyncToken requirement, and the schema itself adds the sparse-update semantics, line replacement, and prohibited-fields guidance. It doesn't add syntax beyond the schema, so a moderate 4.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (Update) and resource (refund receipt) plus the target system (QuickBooks Online). The name is unambiguous against siblings like update_sales_receipt and update_credit_memo, and the description reinforces that distinction.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states the prerequisite of needing Id and the current SyncToken as returned by the last search or write, which implicitly routes the agent to get_refund_receipt/search_refund_receipts first. No explicit exclusions or named alternatives, so it falls short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.